Stern was a member of the French fencing team at the 1908 London Olympics and competed in both the team and individual épée events. During the Games, the French team defeated Denmark (10–6), Great Britain (12–5), and Belgium (9–7) to capture the gold medal (Stern only competed against Denmark). One of his team-mates on the French team was Alexandre Lippmann. In the individual competition at the 1908 Games, Stern won his 1st-round pool, and advanced to the semifinals by finishing 2nd in his second round pool. He was then eliminated in the semifinals after finishing 5th in his pool (the top 4 advanced to the final), and officially finished in 12th place.